Thanks everyone for all the good info!

In the end, this is what i had to do...

I installed pkgsrc/net/libpcap (0.8.3) I then renamed the pcap.h in
/usr/include to pcap.h.old.

After I rebuild ethereal (0.10.9) which now compiled using
/usr/pkg/include/pcap.h instead of NetBSD 2.0's stock pcap.h.

#ethereal -v
ethereal 0.10.9
Compiled with GTK+ 2.6.2, with GLib 2.6.2, with libpcap 0.8.3, with libz
1.1.4,
with libpcre 5.0, with Net-SNMP 5.1.2, without ADNS.

I did discover, that -- as Cliff had mentioned -- even in 0.10.9, if you do
not start ethereal with the command line option '-i ath0' (or whatever
wireless device you have) the 'Link-layer header type' drop down box in
Capture -> Start, will be mangled.

Additionally, you must setup your wireless card device thus:
#ifconfig ath0 media autoselect mediaopt monitor up

I hope this helps some other poor soul in the future...

jam